TechNotes 3: Compatibility of Glasses

Overview

“Compatibility” refers to the properties of glass that allow it to be heat-bonded with another glass such as in a kiln. For many years, it was believed compatibility was solely determined by the properties of expansion in different glasses. This led to an overemphasis on the numerical value of the COE (“coefficient of expansion”) of glasses.

But matching COEs does not accurately predict compatibility. If you have two glasses from different manufacturers and are not sure if they’re compatible, no single piece of information will tell you if they are. They must be tested.